package servlets.module.lesson;

import dbProcs.Getter;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Locale;
import java.util.ResourceBundle;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.owasp.encoder.Encode;
import utils.FindXSS;
import utils.Hash;
import utils.ShepherdLogManager;
import utils.Validate;

/**
 * Unvalidated Redirects and Forwards Lesson <br>
 * <br>
 * This file is part of the Security Shepherd Project.
 *
 * <p>The Security Shepherd project is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.<br>
 *
 * <p>The Security Shepherd project is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE. See the GNU General Public License for more details.<br>
 *
 * <p>You should have received a copy of the GNU General Public License along with the Security
 * Shepherd project. If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Mark Denihan
 */
public class UnvalidatedForwardsLesson extends HttpServlet {

  private static final long serialVersionUID = 1L;
  private static final Logger log = LogManager.getLogger(UnvalidatedForwardsLesson.class);
  private static String levelName = "Unvalidated Redirects and Forwards Lesson";
  private static String levelHash =
      "f15f2766c971e16e68aa26043e6016a0a7f6879283c873d9476a8e7e94ea736f";

  /**
   * User submission is parsed for a valid URL. This is then used to construct a URL object. This
   * URL object is then checked to ensure a valid attack
   *
   * @param tempId User's session stored temporary id
   * @param messageForAdmin Users lesson submission
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    // Setting IpAddress To Log and taking header for original IP if forwarded from proxy
    ShepherdLogManager.setRequestIp(request.getRemoteAddr(), request.getHeader("X-Forwarded-For"));
    log.debug(levelName + " Servlet Accessed");
    PrintWriter out = response.getWriter();
    out.print(getServletInfo());

    // Translation Stuff
    Locale locale = new Locale(Validate.validateLanguage(request.getSession()));
    ResourceBundle errors = ResourceBundle.getBundle("i18n.servlets.errors", locale);
    ResourceBundle bundle =
        ResourceBundle.getBundle("i18n.servlets.lessons.unvalidatedRedirect", locale);

    try {
      HttpSession ses = request.getSession(true);
      if (Validate.validateSession(ses)) {
        ShepherdLogManager.setRequestIp(
            request.getRemoteAddr(),
            request.getHeader("X-Forwarded-For"),
            ses.getAttribute("userName").toString());
        log.debug("Current User: " + ses.getAttribute("userName").toString());
        Cookie tokenCookie = Validate.getToken(request.getCookies());
        Object tokenParmeter = request.getParameter("csrfToken");
        if (Validate.validateTokens(tokenCookie, tokenParmeter)) {
          String tempId = (String) ses.getAttribute("tempId");
          log.debug("tempId = " + tempId);
          String userName = (String) ses.getAttribute("userName");
          String messageForAdmin = request.getParameter("messageForAdmin").toLowerCase();
          log.debug("User Submitted - " + messageForAdmin);
          String htmlOutput = new String();
          boolean validUrl = true;
          boolean validSolution = false;
          boolean validAttack = false;
          try {
            URL csrfUrl = new URL(messageForAdmin);
            log.debug("Url Host: " + csrfUrl.getHost());
            log.debug("Url Port: " + csrfUrl.getPort());
            log.debug("Url Path: " + csrfUrl.getPath());
            log.debug("Url Query: " + csrfUrl.getQuery());
            validSolution = csrfUrl.getPath().toLowerCase().equalsIgnoreCase("/user/redirect");
            if (!validSolution) {
              log.debug("Invalid Solution: Bad Path or Above");
            }
            validSolution =
                csrfUrl.getQuery().toLowerCase().startsWith(("to=").toLowerCase()) && validSolution;
            if (!validSolution) {
              log.debug("Invalid Solution: Bad Query or Above");
            }
            if (validSolution) {
              log.debug(
                  "Redirect URL Correct: Now checking the Redirected URL for valid CSRF Attack");
              int csrfStart = 0;
              int csrfEnd = 0;
              csrfStart = csrfUrl.getQuery().indexOf("to=") + 3;
              csrfEnd = csrfUrl.getQuery().indexOf("&");
              if (csrfEnd == -1) {
                csrfEnd = csrfUrl.getQuery().length();
              }
              String csrfAttack = csrfUrl.getQuery().substring(csrfStart, csrfEnd);
              log.debug("csrfAttack Found to be: " + csrfAttack);
              validAttack =
                  FindXSS.findCsrfAttackUrl(
                      csrfAttack,
                      "/root/grantComplete/unvalidatedredirectlesson",
                      "userId",
                      tempId);
            }
          } catch (MalformedURLException e) {
            log.error("Invalid URL: " + e.toString());
            validUrl = false;
            validSolution = false;
            validAttack = false;
            messageForAdmin = "";
            htmlOutput = "Invalid URL";
          }

          if (validSolution && validAttack) {
            htmlOutput =
                "<h2 class='title'>"
                    + bundle.getString("result.wellDone")
                    + "</h2>"
                    + "<p>"
                    + bundle.getString("result.youDidIt")
                    + "<br />"
                    + bundle.getString("result.resultKey")
                    + " <a>"
                    + Hash.generateUserSolution(
                        Getter.getModuleResultFromHash(
                            getServletContext().getRealPath(""), levelHash),
                        (String) ses.getAttribute("userName"))
                    + "</a>";
          }
          if (validUrl) {
            log.debug("Adding message to Html: " + messageForAdmin);
            htmlOutput +=
                "<h2 class='title'>"
                    + bundle.getString("response.messageSent")
                    + "</h2>"
                    + "<p><table><tr><td>"
                    + bundle.getString("response.sentTo")
                    + ": </td><td>administrator@SecurityShepherd.com</td></tr>"
                    + "<tr><td>"
                    + bundle.getString("response.message")
                    + ": </td><td><a href='"
                    + Encode.forHtmlAttribute(messageForAdmin)
                    + "'>"
                    + Encode.forHtml("" + bundle.getString("response.linkFrom") + " " + userName)
                    + "</a></td></tr></table></p>";
          }
          log.debug("Outputting HTML");
          out.write(htmlOutput);
        }
      }
    } catch (Exception e) {
      out.write(errors.getString("error.funky"));
      log.fatal(levelName + " - " + e.toString());
    }
    log.debug("End of " + levelName + " Servlet");
  }
}
